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Marine isotopic stage
 
 
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Marine isotope stages (MIS) or marine oxygen-isotope stages, in older literature called oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate
Paleoclimatology

Paleoclimatology is the study of climate change taken on the scale of the entire history of Earth. It uses records from ice sheets, tree rings, sediment, and rock s to determine the past state of the climate system on Earth....
, deduced from oxygen isotope data
Oxygen isotope ratio cycle

Oxygen isotope ratio cycles are cyclical variations in the ratio of the mass of oxygen with an Atomic mass of 18 to the mass of oxygen with an atomic weight of 16 present in some substance, such as polar ice or calcite in ocean core samples....
 reflecting temperature curves derived from data from deep sea core sample
Core sample

A core sample is a cylindrical section of a naturally occurring medium consistent enough to hold a layered structure. Most cores are obtained by drilling into the medium, for example the earth, with a hollow steel tube called a corer....
s. The significance of the data
Each stage is a period of higher or lower temperature on a graph of mean temperature (y-axis) versus millions, hundreds of thousands or thousands of years (x-axis).






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Marine isotope stages (MIS) or marine oxygen-isotope stages, in older literature called oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate
Paleoclimatology

Paleoclimatology is the study of climate change taken on the scale of the entire history of Earth. It uses records from ice sheets, tree rings, sediment, and rock s to determine the past state of the climate system on Earth....
, deduced from oxygen isotope data
Oxygen isotope ratio cycle

Oxygen isotope ratio cycles are cyclical variations in the ratio of the mass of oxygen with an Atomic mass of 18 to the mass of oxygen with an atomic weight of 16 present in some substance, such as polar ice or calcite in ocean core samples....
 reflecting temperature curves derived from data from deep sea core sample
Core sample

A core sample is a cylindrical section of a naturally occurring medium consistent enough to hold a layered structure. Most cores are obtained by drilling into the medium, for example the earth, with a hollow steel tube called a corer....
s.
Five Myr Climate Change

The significance of the data


Each stage is a period of higher or lower temperature on a graph of mean temperature (y-axis) versus millions, hundreds of thousands or thousands of years (x-axis). The cycles were found to correspond to terrestrial evidence of glacials and interglacials. A graph of the entire series of stages then revealed hitherto unknown and unsuspected advances and retreats of ice and also filled in the details of the stadials and interstadials. More recent core samples of today's glacial ice substantiated the cycles through studies of ancient pollen
Pollen

Pollen is a fine to coarse powder consisting of Gametophyte , which produce the male gametes of spermatophyta. A hard coat covering the pollen grain protects the sperm cells during the process of their movement between the stamens of the flower to the pistil of the next flower....
 deposition. Currently a number of methods are making additional detail possible.

The number of stages


Each stage represents a glacial, interglacial, stadial
Stadial

A stadial is a period of colder temperatures during an interglacial, of insufficient duration or intensity to be considered a glaciation, or glacial period....
 or interstadial. Interglacials are odd-numbered; glacials are even numbered, one for each stage, starting from the present and working backward in time. For example, the Holocene
Holocene

The Holocene is a geological Epoch which began approximately 11,700 years ago . According to traditional geological thinking, the Holocene continues to the present....
 is MIS1, or O-stage 1, or just stage 1. The previous interglacial is MIS5, or O-stage 5, or just stage 5.

Exceptionally, MIS2-4 refer to the last glacial, because when initially interpreted MIS3 looked like an interglacial.

Stadials and interstadials are identified by a letter following the corresponding glacial or interglacial: 5a, 5b, etc. The dates of the stages were obtained by calibrating the graph on known dates by other methods.

MIS 11 of approximately 400ka is the most similar to MIS 1. A difference that has puzzled scientists is that CO2
Carbon dioxide

Carbon dioxide is a chemical compound composed of two oxygen atoms covalent bond to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state....
 levels remained steady or rose during MIS1 (before the industrial era), when by analogy to past interglacials, they should have been steadily decreasing over the last 5000 years. This is the basis of the Early anthropocene hypothesis.

Matching the stages to named periods


Matching the stages to named periods proceeds as new dates are discovered and new regions are explored geologically. The process is challenging, however, since the marine isotopic record appears more complete and detailed than any terrestrial equivalents. The MIS data for the last 2.5 million years show "about fifty climate cycles […] so far not even half these cycles have been identified on land […]" A current timeline of glaciation
Timeline of glaciation

There have been four major periods of Ice age in the Earth's past. The second, and possibly most severe, is estimated to have occurred from 850 to 635 Annum#Multiples_of_an_.22annum.22 ago, in the Neoproterozoic) and it has been suggested that it produced a "Snowball Earth" in which the earth iced over completely....
 for the Plio-Pleistocene
Pleistocene

The Pleistocene is the epoch from 1.8 million to 10,000 years Before Present covering the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
 represents a version of this ongoing endeavor.

See also

  • Ice Age
    Ice age

    The general term "ice age" or, more precisely, "glacial age" denotes a geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in an expansion of continental ice sheets, polar ice sheets and alpine glaciers....
  • Timeline of glaciation
    Timeline of glaciation

    There have been four major periods of Ice age in the Earth's past. The second, and possibly most severe, is estimated to have occurred from 850 to 635 Annum#Multiples_of_an_.22annum.22 ago, in the Neoproterozoic) and it has been suggested that it produced a "Snowball Earth" in which the earth iced over completely....